1-hydroxy-anthracene-carboxylic acid and a process of making it



Patented June 13, 1933 UNITED STATES PATENT OFFICE LEOPOLD LASKA AND OSKAR HALLER, 0F

ASSIGNORS TO GENERAL ANILINE VTORKS,

TION OF DELAWARE OFFENBAGH-ON-THE-MAIN, GERMANY, INCL, OF NEW YORK, N. Y., A CORPORA- No Drawing. Application filed May 20,1932 Serial No. 612,631 and in Germany June 4, 1931..

following probable formula:

OE AUCOOH 0v We have found that a l-hydroxy-anthracene-carboxylic acid is obtainable by heating to a temperature of 210 C. to 250 C. an alkali metal salt of 1-hydroXy-anthracene with carbon-dioxide at a pressure of 50 atmospheres to about 120 atmospheres. As the carboxylic acid, thus obtained, exhibits a bluish-black coloration when its alcoholic solution is mixed with ferric chloride solution, the carboxylic acid group is-presumed to have entered into the 2-position.

The new carboxylic acid is a valuable intermediate product for the preparation of dyestuffs.

The following example servesto illustrate the invention, but it is not intended to limit it thereto, the parts being by weight:

19 1 parts of l-hydroxy-anthraoene are dissolved with 56 parts of potassium hydroxide and 500 parts of water in an autoclave probenzene in the form of yellow leaflets melting at 200 C. with decomposition. The acid. gives in alcoholic solution a bluish-black colhydroxy-anthracene.

We claim:

1. The process which comprises heating to a temperature of 210 C. to 250 C. an alkali metal salt of l-hydroxy-anthracene with carbon dioxide at a pressure of 50 atmospheres to about 120 atmospheres.

2. As a new product, the compound of the following probable formula:

on OAUCOOH crystallizing from o-dichlorobenzene in the tures.

LEOPOLD LASKA. OSKAR HALLER.

vided with a stirrer; thereupon the water is i distilled off, finally in vacuo, while providing an atmosphere of nitrogen in order to prevent oxidation,- obtained is completely dried. After cooling, carbon dioxide is introduced into the reaction mass while gradually increasing the pressure to 90 atmospheres, the whole is then heated to 210 C. to 220 C. and heating is continued for 12 hours. The melt is allowed until the potassium salt to cool and then dissolved in hot water, the 7 solution is filtered with suction and the car boxylic means of hydrochloric acid. It may bepurified by dissolving it in dilute sodium acetate acid, thus obtained, is precipitated by solution, filtering it with suction and again I precipitating it by means of hydrochloric acid. The said carboxylic acid has a yellow coloration and crystallizes from o-dichloro- 

